defmodule Aoc2023.Day7 do
  use Aoc2023

  def hand_type(values) do
    values
    |> Enum.frequencies()
    |> then(fn freq ->
      {jokers, freq_} = freq |> Map.pop(0, 0)
      common = freq_ |> Enum.max_by(pipe(elem(1))) |> elem(0)
      freq_ |> Map.update!(common, &(&1 + jokers))
    end)
    |> Enum.map(pipe(elem(1)))
    |> Enum.sort(:desc)
    |> case do
      [5] -> 6
      [4, 1] -> 5
      [3, 2] -> 4
      [3, 1, 1] -> 3
      [2, 2, 1] -> 2
      [2, 1, 1, 1] -> 1
      [1, 1, 1, 1, 1] -> 0
    end
  end

  def parse(input) do
    fn rankings ->
      input
      |> lines
      |> Enum.map(&String.split/1)
      |> Enum.map(fn [hand, bid] ->
        {
          hand |> String.to_charlist() |> Enum.map(&Map.get(rankings, &1)),
          bid |> String.to_integer()
        }
      end)
      |> Enum.sort_by(elem(0) |> hand_type &&& elem(0), :asc)
      |> Enum.with_index(1)
      |> Enum.map(fn {{_, bid}, index} -> bid * index end)
      |> Enum.sum()
    end
  end

  @ranking [
    ?2,
    ?3,
    ?4,
    ?5,
    ?6,
    ?7,
    ?8,
    ?9,
    ?T,
    ?J,
    ?Q,
    ?K,
    ?A,
  ] |> Enum.with_index(1) |> Map.new

  def part1(input) do
    input.(@ranking)
  end

  def part2(input) do
    input.(@ranking |> Map.put(?J, 0))
  end
end